Many people are accustomed to seeing an image in which a person is a photographic subject. If a color of a person's skin in the image is not properly reproduced, the reproduced image may lead to a sense of incongruity to the viewer. Moreover, in a case where a photograph of a person who wears a red hat or red clothes is taken, the person's skin may look bluish even if the skin color itself is properly reproduced. There is a visual sense characteristic that the skin color does not look proper due to the effect of contrast between the skin color and the background color.
To improve an impression of a person photographed in an image, image processing may be performed so that a person's skin color is changed to a color different from the actual condition. For example, if the color of a woman's skin in the image is made more fair or the color of a man's skin in the image is made more dark, the impression of the person within the image may be changed. In a case of images used for commercial purposes, such as advertisement and promotion, it is demanded to give an impression that a person and goods are suitably fitted to each other. In this case, image processing which adjusts the skin color to such appearance becomes more important. Moreover, in a case of a print market in which photographs are left as important recollections, such as a photograph book, the highest priority matter is to reproduce the skin color so that a person's impression in an image may improve.
An image processing method has been proposed in which color components of pixels of a skin area in an image are acquired using three attributes of brightness, saturation, and hue of the pixels and the color components of the skin area are adjusted to change partially distributions represented by two of the three attributes so that a skin color of a person in an image is adjusted. For example, see Japanese Laid-Open Patent Publication No. 2007-158824.